Variable pitch propeller mechanism



@ci. 111 1949., J. REMMEN VARIABLE PITCH PROPELLER MECHANISM Filed Mayll, 19%

4 Sheets-Sheet l INVENTUR. g BY 7,14%

@cfi. M, 1949., J. REMMEN VARIABLE PITCH PROPELLER MECHANISM 4Sheets-Sheet 2 Filed May 11, 1944 & m

Oct. 3]., 1949, J. REMMEN VARIABLE PITCH PROPELLER MECHANISM 4Sheets-Sheet 3 Filed May ll, l9 44 INVENTOR 0a., M, 1949. J. REMMEN I2,484,739

VARIABLE PITCH PROPELLER MECHANISM Filed May 11, 1944 4 Sheets-Sheet 43, 7 d INVENTOR.

By Wazgu oyad Patented Oct. 11, 1949 UNITED STATES PATENT OFFICE I2,484,139 VARIABLE PITCH PROPELLER MECHANISM J orgenRemmen, Pittsburgh,Pa.

Application May 11, 1944, Serial No. 535,084

to constantly obtain a balanced thrust on the blades.

It is another object of the invention to provide a variable pitchpropeller mechanism responsive to the twisting moment of the propellerblades which shall be of simple, compact and durable mechanicalconstruction embodying a minimum number of wearing parts.

It is still another object of the invention to provide a variable pitchpropeller mechanism in which the pitch adjustment is operative inresponse to the speed of rotation and the twisting moment of the blades,to maintain constant engine speed under all operating conditions.

Still a further object of the invention is the provision of a variablepitch propeller mechanism of the above-designated character in which thedegree of pitch setting of the blades may be manually controlled.

Still a further object of the invention is the provision of variablepitch propeller mechanism of the above designated character for use inoppositely rotating propellers which shall have pitch adjusting meanscommon to both propellers.

These and other objects of the invention will become more apparent froma consideration of the accompanying drawings constituting a. part hereofin which like reference characters designate like parts, and in whichFig. 1 is a top plan view, partially in section, of a propellermechanism embodying the principles of this invention;

Fig. 2 a vertical section, partially in elevation, of the propellerstructure of Fig. 1, Figs. 1 and 2 illustrating the bottom propeller ofa pair of oppositely rotating propeller blades;

Fig. 3 a top plan view, partially in section, of the upper blademechanism;

Fig. 4 a vertical cross-sectional view, partially in elevation, of themechanism shown in Fig. 3;

Fig. 5 a side elevational view, partially in crosssection, of oppositelyrotating variable pitch propeller mechanism and drive shafts therefor;

Fig. 6 a top plan view showing the cover plate in place;

Figs. 7, 8 and 9 are side elevations, partially in sections, and topplan views, respectively, of a modified form of variable pitchoppositely rotating propeller blades.

Cal

(Cl. I'm-160.42)

With reference to Figs. 1 to 6 inclusive of the drawings, the structuretherein illustrated comprises a fixed or stationary housing I, Fig. 5,in which a hollow drive shaft 2 is journaled by roller bearings 3 and3a, the shaft 2 having a propeller hub I mounted thereon for rotationtherewith. A second hollow shaft 5 is disposed within the hollow shaft 2and is connected to a propeller hub which is mounted for rotation at theend thereof, shaft 5 being journaled in the hollow shaft 2 by rollerbearings l and la. Shaft 2 is provided with a bevel gear 8 and shaft 5with a bevel gear 9 which are driven by a pinion l0 connected to theengine shaft 6 l for driving the propeller hubs. A free-wheeling clutchl2 may be connected in the engine shaft to permit windmilling of theblades when the power is cut oif. Disposed within the hollow shaft 5 isa control rod 83 connected to a lever it fulcrumed at it and operated bya link it connected to a hand lever H for adjusting the pitch setting ofthe propeller blades, as will be hereinafter explained. A disconnectingclutch, not shown, may be provided in the engine shaft to permitoperation of the motor without rotation of the blades.

The construction of the propeller blades and hubs is more clearly shownin Figs. 1 to 4 of the drawings which show a pair of propeller bladeroots 98 mounted in sockets is having trunnions 20 disposed in bearingsit of the hubs t and ii. The blade roots are pivotally mounted in thesocket members by pins 22 and are restrained in their pivotal movementby leaf springs 23, the tension of which is regulated by ferrules 25.The blade sockets iii are free to pivot on the trunnions 2e and arerestrained in their pivotal movement by leaf springs 25. The bladesockets are also rotatably mounted in journal bearings 26 of thetrunnion members and thrust bearings 2'! are provided intermediate thetrunnion bearing and gear segments 28. Bolts 29 extend through gearsegments 28,bearings 21 and 26 and have threaded connection at 38 withthe blade socket l9.

The gear segments 28 have gear teeth 3| which interact with the teeth ofgear racks 32 mounted on levers 33 that rest against stops 34. The endsof the levers are provided with trunnions 35 that operate in the groove36 of a slip ring 31 that is slidably mounted on the shaft 5 andconnected by a cross pin 38 with the control rod l3, as shown in Figs. 1and 2, the levers 33 of the upper blade member being pivotally mountedto trunnions 39 that are fixed to the end of the control rod l3, asshown in Figs. 3 and 4. When the control rod is moved vertically throughthe hand control 3 lever I! of Fig. 5, the positions of the gear racks32 are correspondingly changed, which varies the degree of pitch of theblades as will be hereinafter explained. Pivot pins 22 are held againstdisplacement by plates 22a which are fastened by screws 2212 as shown inFigs. 1 and 3.

The operation of the above-described mechanism is briefly as follows.The hollow drive shafts 2 and 5 are rotated in opposite directions bythe gear in of the propeller engine and the pitch of the propellerblades is at normal setting when lever i1 is in the position shown inFig. 5. As the blades revolve the centrifugal moment on the air foilsection of the blade will tend to pivot the blades on their trunnions20. The pivotal movement will effect relative movement of the teeth ofthe gear segments 28 with the racks 32 causing angular adjustment of theblades to vary their pitch, thereby obtaining a balanced lift in bothblades regardless of air currents where for example the propellers areemployed on helicopter aircraft. If when employed as lifting propellersfor helicopters the movement of the craft is in the direction of a headwind, the blade advancing into the wind will, because of the pivotalmovement of the blade upward on its trunnions 20, be subjected to adecreasing pitch setting, while on the return movement of the blade inthe slip stream it will drop to effect an increased pitch setting,thereby maintaining the propulsion force or thrust on both bladesconstant. By moving the control lever I1 and raising or lowering thecontrol rod i3, the rack arms 33, which are pivoted on the trunnionbearings 2|, will effect a pitch change to increase or decrease theamount of pitch ad- Justment as the blades revolve. In case of enginefailure the free-wheeling clutch i2 is connected to allow the blades towindmill as an Autogiro. The hand control is provided especially forregulating the degree of pitch adjustment in climbing to maintainmaximum horsepower output of the motor which permits the employment ofengines of smaller horsepower capacity on the one hand and allows formaximum climbing speed when larger horsepower engines are employed.

By means of the hand control of the pitch setting mechanism, the bladesmay be power driven for lowering the aircraft and the aircraft can bemaintained at any desired elevation by merely adjusting the pitchsetting by the manual control.

When the propeller mechanism is employed on aircraft of the wing type asa propulsion propeller, the pitch of the blades may be set by thecontrol lever I! to obtain maximum horsepower output of the propellerengine for the take-oil. and adjusted for cruising to a pitch setting tomaintain a constant engine speed. Because, as hereinbefore described,pivotal movement of the blade on its trunnion supports will effect acorresponding pitch setting, and further because such pivotal movementis induced by the twisting moment which is a factor of the propulsionforce or load on the blade, the propellers will rotate at a constantspeed for the particular pitch setting to which the manual control hasbeen adjusted by lever II. The device thus operates as a constant speedpropeller mechanism and constitutes a governor control for the propellerengine.

The pivoted joint 22 is employed on relatively long blades when used onhelicopters to permit the blades to lag slightly when initially rotated.These pivotal connections may therefore be eliminated on propellerblades used in propulsion propeller mechanisms for the wing typeaircraft.

Also in the latter use the springs 25 can be adiusted to tilt the bladeforward when the motor is cut down to a landing speed, which woulddecrease thepitch setting of the blade.

In Figs. 7 to 9 inclusive is shown a modified form 01' helicoptervariable pitch propeller mechanism in which the numeral 40 designatesthe stationary housing, ll the lower drive shaft and 42 the drive shaftfor the upper blade. The control rod 43 is connected by a lever 44 to anadjusting mechanism operated by a hand wheel 45. The numeral 45designates the hub for the lower blades and 41 the hub for the upperblades, the hubs being journaled by roller bearings 48 and 49 on theshaft 4| and bearings 50 and 5| on the upper drive shaft 42, thearrangement being such that the hubs may windmill in one direction oftheir rotation as when the engine stops. Shaft 4| is driven throughbevel gear 52 and shaft 42 through bevel gear 53 by gear wheel 54connected to the engine shaft 55. The blades 56 are mounted on the bladeroots 5'! which extend through trunnion members 58 in which they arejournaled. The ends of the blade roots 51 are provided with cranks 59,the crank pins 60 of which operate in grooves SI of slip rings 62 and62a which are adjustable by the control rod 43 through the manipulationof the hand wheel 45. As will be apparent from Figs. 7 and 8 of thedrawings, the lifting and lowering movement of the wings or blades 55will cause rotation of the blades by virtue of their crank connectionswith the slip rings to effect pitch adjustment as they are revolving inthe manner described in connection with the remaining figures of thedrawings.

Although several embodiments of the invention and its uses have beenherein illustrated and described, it will be evident to those skilled inthe art'that'various modifications may be made in the details ofconstruction without departing from the principles herein set forth'.

I claim:

1. In a variable pitch propeller mechanism, a hub structure, bladesockets having trunnion members mounted in said hub for movement in aplane transversely of the plane of rotation of the blade, blades mountedfor rotary movement in said sockets, and segment gears mounted on theinner ends of the blades to be rotatable therewith, gear racks pivotallymounted on said trunnion members for interacting with said segment gearsto vary the pitch of the blades in response to pivotal movement of theblade on the trunnion member, and manual means connected to said a gearracks for actuating the latter to adjust pitch setting of the bladesindependently of pivotal movement .of the blades on their trunnionsupports.

2. In a variable pitch propeller mechanism, a hub structure, a pluralityof blade sockets mounted on trunnions in said hub structure forreceiving the blade roots therein to allow pivotal movement of theblades relative to said hub in a plane transversely .of the plane ofrotation of the blade, blade members pivotally mounted on the bladeroots to be movable in a plane opposite to the plane of pivotal movementof the socket members, springs mounted on the roots and on the bladesockets in the path of movement of the blades and sockets for limitingand restraining the relative movement of the blades and blade sockets,said blades having segment gears mounted on the inner ends thereof andgear racks pivotally mounted on said trunnion members having teethinteracting with the teeth of said segment 5 gears, said segment gearsbeing mounted on levers pivotally mounted on the blade socket trunnionshaving arms for interacting with a slip ring, and

an adjustable slip ring for said arms whereby said racks may be actuatedaround their trunnion supports to subject the segment gears to rotarymovement to vary the pitch of the blades independently oftilting'movement of the blades on their trunnion supports.

J ORGEN REMMEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED s'ra'res PATENTS Number Number

